Relay armature mounting



April 14, 1959 F. A. GLASSOW RELAY ARMATURE MOUNTING Filed Sept. 29, 1954 II'IA INVENTOR. F'an/r 'yn A, Giassou/ ra 'w ATTORNEYS 2,882,461 RELAY ARMATURE MOUNTING Franklyn A. Glassow, Rockford, Ill., assignor to Barber- Colman Company, Rockford, Ill., a corporation of Illinois Application September 29, 1954, Serial No. 459,061

3 Claims. (Cl. 317198) This invention relates to the mounting of the annature in a relay of the type shown in US. Letters Patent No. 2,443,784 in which two torsion arms project from opposite sides of the armature proper and are attached to crosspieces clamped between the pole pieces of the relay, the latter being of the polarized type and extremely sensitive to current fluctuations in its winding.

The primary object of the present invention is to improve the mounting of the armature in the above relay so as to obtain greater stability in the overall performance of the relay in service use and over prolonged periods.

A more detailed object is to mount the torsion arms of the armature in a new and improved way so as to avoid any possible displacement of the arms during service use.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in Which:

Figure 1 is a side elevational view of a relay embodying the novel features of the present invention, the casing being shown in section.

Figs. 2 and 3 are sectional views taken along the lines 22 and 33 respectively of Figs. 1 and 2.

Fig. 4 is an exploded perspective view of the armature and contact support assembly.

Fig. 5 is a perspective view of the armature and contact support assembly.

In the drawings, the improved armature mounting is shown incorporated in a relay of the patented type in which opposite ends of a generally flat plate-like armature 11 of magnetic material are disposed in air gaps between two pairs of flat opposed faces 12 of pole pieces 13, 14, 15 and 16 continuously threaded by flux from two permanent magnets 17, the flux being varied in density in response to current fluctuations in a winding 18 encircling the armature and disposed between the pole pieces of the two pairs. Herein, the pole pieces are integral ears bent inwardly toward each other from opposite sides of two bridge members 19 and 20 spanning and clamped against opposite ends of the magnets by draw bolts 21, this assembly being mounted on a supporting base 22.

A flat elongated strip 23 of conducting material such as beryllium copper lies flat against one side of the armature and is secured thereto by rivets 24. At its opposite ends, the strip extends beyond the armature and the pole pieces and carries contacts 25 which cooperate with fixed contacts 26 to form the relay switches, the fixed contacts being carried by but insulated from brackets 27 secured to and forming part of the lower pole pieces 15 and 16. The rivets are anchored in a fiat plate 28 clamped against the opposite side of the armature.

The rivets 24 also serve to secure the armature 11 to a thin plate 29 of resilient material such as hardened beryllium copper which in this instance is disposed between the contact strip 23 and the armature and is seated in a transverse groove in the latter. Formed integral with the plate 29 and projecting from opposite sides of the armature are United States Patent Office 2,882,461 Patented Apr. 14, 1959 generally fiat torsion arms 30 which at their outer ends are connected rigidly to crossbars 31 lying between the .pole faces 12 and clamped firmly by the latter.

Heretofore, the crossbars in relays of the above character have been made relatively thin and disposed perpendicular to the pole faces so as to take advantage of the relative hardness of the beryllium copper and the softness of the magnetic iron of the pole faces to form a positive interlock for holding the ends of the torsion arms more precisely positioned. That is to say, the edges of the hardened crossbars under the applied clamping pressure bite into the softer iron with the result that each crossbar is held positively against twisting in service use.

The relay thus constructed possessed the desired sensitivity in initial service use but became unstable in prolonged service use, such instability increasing progressively. I have discovered that this difficulty is due to the very precautionary measures which sought to provide the initial stability, namely the construction of the crossbars 31 and the manner of attachment of the torsion arms 30 thereto. That is to say, under the repeated and variable stresses encountered in service use, the hardened edges of the thin crossbars cut deeper and deeper into the softer pole pieces and in this way changed the effective location of the points of anchorage of the outer ends of the torsion arms. This change, although extremely minute, is nevertheless suflicient to reduce substantially the stability of the relay whose chief attribute is its extreme sensitivity.

Based on the foregoing discovery, the present invention contemplates a novel construction of the crossbars 31 and manner of securing them to the torsion arms 30 and the pole faces 12. For this purpose, flat crosspieces 32 lying in the plane of the torsion arms 30 are first formed integral with the outer ends of the torsion arms and these thin crosspieces are attached to wider and more rigid bars 36 which are clamped between the pole faces and engage the latter over a comparatively large area. The crosspieces 32 lie flat against and are attached directly to surfaces 33 of the crossbars 36 which may be composed of the same material as the crosspieces. To avoid sinking of the bars 36 into the pole pieces 13, 14, 15, and 16, the increased contact area is achieved by making the bars of substantial thickness, equal to several times the thickness of the torsion arms 30 and the crosspieces 32 in a direction paralleling the pole faces 12.

In the present instance, the crosspieces 32 which extend laterally from opposite side edges of the torsion arms 30 are shorter than the armature 11 and the bars 36 and are welded to the flat surfaces 33 which are undercut below the fiat surfaces 34 on one side of each bar to locate the opposite armature ends 10 midway between the pole faces 12. The bars 32 are of rectangular cross section and the thickness of each bar surface 34 in a direction parallel to the pole faces is approximately four times the thickness of each torsion arm 30 and crosspiece 32. The resulting contact area between each pole face and fiat bar surface 34 is sutficient to prevent sinking of the bars into the pole pieces under the required clamping pressure.

In addition to avoiding indentation of the pole pieces by the crossbars 31, the substantial thickness of the bars stiifens the same against twisting about their own longitudinal axes. This stiffness of the bars plus the rigidity of the connection between the torsion arms 30 and the bar surfaces 33 afforded by securing the crosspieces 32 fiat against these surfaces insures that the points of anchorage of the arms remain fixed precisely throughout the service life of the relay. As a result, stability in the performance of the relay both initially and after prolonged service use is substantially improved.

I claim as my invention:

1. In a relay, the combination of, a first pair of pole pieces having flat faces opposing each other to define a first elongated air gap, a second pair of pole pieces laterally spaced from said first pair and having elongated flat faces opposing each other to define a gap paralleling and lying in a common plane with said first gap, two elongated rigid bars of non-magnetic material laterally spaced apart lengthwise of said gaps and each bridging the gaps with opposite end portions of each bar extending into the respective gaps and clamped between said pole faces defining the gaps, means on said bar end portions having substantial width lengthwise of said gaps and providing large fiat areas of bearing contact with said pole faces to prevent the bars from tilting about their longitudinal axes and sinking into said pole pieces under the clamping forces between the bars and the pole faces, an elongated armature disposed between said bars and bridging said gaps with opposite end portions of the armature extending into the gaps and having a thickness less than the spacing of the opposed pole faces at each gap, a plate of -nonmagnetic material secured to said armature and having integral torsion arms projecting in opposite directions transversely of and beyond said armature and secured at their outer ends to said bars to support the armature on the bars for rotation about the arms and movement of said armature end portions within said gaps and toward and away from said pole faces.

2. In .a relay, the combination of, a first pair of pole pieces having fiat faces opposing each other to define a first elongated air gap, a second pair of pole pieces laterally spaced from said first pair and having elongated flat faces opposing each other to define a gap paralleling and lying in a common plane with said first gap, two elongated rigid bars of non-magnetic material laterally spaced apart lengthwise of said gaps and each bridging the gaps with opposite end portions of each bar extending into the respective gaps and clamped between said pole faces defining the gaps, means on said bar end portions having substantial Width lengthwise of said gaps and providing large flat areas of bearing contact with said pole faces to prevent the bars from tilting about their longitudinal axes and shaking into said pole pieces under the clamping forces between the bars and the pole faces, an elongated armature disposed between said bars and bridging said gaps with opposite end-portions of the armature extending into the gaps and having a thickness less than the spacing of the opposed pole faces at each gap, a thin plate of nonmagnetic material secured to said armature and having integral torsion arms lying in the plane of the plate and extending transversely of and beyond the armature and in opposite directions from the plate intermediate the ends of the armature, and flat crosspieces extending transversely of and formed integral with said arms at the outer ends of the arms and secured flatwise against said bars to support said armature on the bars for rotation about the arms and movement of said armature end portions within said gaps and toward and away from said pole faces.

3. In a relay, the combination of, a first pair of pole pieces having fiat faces opposing each other to define a first elongated air gap, a second pair of pole pieces laterally spaced from said first pair and having elongated flat faces opposing each other to define an air gap paralleling and lying in a common plane with said first gap, two rigid bars of non-magnetic material laterally spaced apart lengthwise of said gaps and bridging the gaps with opposite end portions of each bar extending into the respective gaps and providing flat surfaces which are clamped against said pole faces and have a substantial width lengthwise of the gaps to contact the faces over a large bearing area,

each of said bars between said end portions having a recess opening laterally from one side of the bar with a fiat intermediate surface paralleling said fiat surfaces on the end portions of the bar and defining the bottom of the recess, an elongated armature disposed between said bars and bridging said gaps with opposite end portions of the armature extending into the gaps and having a thickness less than the spacing of the opposed pole faces at each gap, a thin plate of non-magnetic material secured to said armature and having integral flexible torsion arms formed integral with the plate in the plane thereof and extending in opposite directions transversely of and beyond the armature intermediate said armature end portions, and fiat crosspieces extending transversely of and formed integral with said arms at the outer ends thereof and secured flatwise against said flat intermediate bar surfaces to support said armature on the bars for rotation about the arms and movement of said armature end portions within said gaps and toward and away from said pole faces.

References Cited in the file of this patent UNITED STATES PATENTS 2,002,871 Sharp May 28, 1935 2,443,784 Bullen et al June 22, 1948 2,491,140 Sweger Dec. 13, 1949 2,580,123 Pfieger Dec. 25, 1951 2,727,191 Kinsley Dec. 13, 1955 2,761,929 McLellan Sept. 4, 1956 

